US President Barack Obama (C) celebrates with vice president Joe Biden and his family members along with the First Family members on election night in Chicago on November 7, 2012. Obama swept to re-election, forging history again by transcending a slow economic recovery and the high unemployment which haunted his first term to beat Republican Mitt Romney. (Credit: JEWEL SAMAD/AFP/Getty Images)

US-VOTE-2012-ELECTION-OBAMA

US President Barack Obama (C) applauds at supporters on election night in Chicago on November 7, 2012. Obama swept to re-election, forging history again by transcending a slow economic recovery and the high unemployment which haunted his first term to beat Republican Mitt Romney. (Credit: JEWEL SAMAD/AFP/Getty Images)

US-VOTE-2012-ELECTION-OBAMA

US President Barack Obama, First Lady Michelle and daughters Sasha (L) and Malia (R) wave to supporters on election night in Chicago on November 6, 2012. Obama swept to re-election, forging history again by transcending a slow economic recovery and the high unemployment which haunted his first term to beat Republican Mitt Romney. (Credit: JEWEL SAMAD/AFP/Getty Images)

INDIA-US-ELECTIONS

Supporters of re-elected US President Barack Obama pose after a breakfast meeting following the announcement of US Election results in Bangalore on November 7,2012. President Obama won a second term as the US President on Tuesday night, overcoming concerns about the fragile economic recovery by soundly defeating Republican nominee Mitt Romney. (Credit: Manjunath Kiran/AFP/Getty Images)

Supporters of US President Barack Obama celebrate during Obama's victory speech on election night November 7, 2012 in Chicago, Illinois. President Barack Obama swept to re-election, forging history again by transcending a slow economic recovery and the high unemployment which haunted his first term to beat Republican Mitt Romney. (Credit: JEWEL SAMAD/AFP/Getty Images)

US-VOTE-2012-ELECTION-OBAMA

US Vice President Joe Biden hugs US President Barack Obama as they celebrate their victory on election night November 7, 2012 in Chicago, Illinois. (Credit: ROBYN BECK/AFP/Getty Images)

US-VOTE-2012-ELECTION-OBAMA

US Vice President Joe Biden celebrates on election night November 7, 2012 in Chicago, Illinois. Republican Presidential candidate Mitt Romney has conceded the race to US President Barack Obama. (Credit: ROBYN BECK/AFP/Getty Images)

2012 Presidential Election Night - New York City Atmosphere

November 6, 2012 in New York City. (Credit: Mike Coppola/Getty Images)

US-VOTE-2012-ELECTION-ROMNEY

US Republican presidential candidate Mitt Romney and his wife Ann leave the stage on election night November 7, 2012 in Boston. President Barack Obama swept to re-election Tuesday, forging history again by transcending a slow economic recovery and the high unemployment which haunted his first term to beat Republican Mitt Romney. (Credit: EMMANUEL DUNAND/AFP/Getty Images)

US-VOTE-2012-ELECTION-OBAMA

Confetti falls during a celebration of the re-election of US President Barack Obama on election night November 7, 2012 in Chicago, Illinois. (Credit: SAUL LOEB/AFP/Getty Images)

during Mitt Romney's campaign election night event at the Boston Convention & Exhibition Center on November 7, 2012 in Boston, Massachusetts. After voters went to the polls in the heavily contested presidential race, networks projected incumbent U.S. President Barack Obama has won re-election against Republican candidate, former Massachusetts Gov. Mitt Romney. (Credit: Alex Wong/Getty Images)

during Mitt Romney's campaign election night event at the Boston Convention & Exhibition Center on November 7, 2012 in Boston, Massachusetts. After voters went to the polls in the heavily contested presidential race, networks projected incumbent U.S. President Barack Obama has won re-election against Republican candidate, former Massachusetts Gov. Mitt Romney. (Credit: Joe Raedle/Getty Images)

2012 Presidential Election Night - New York City Atmosphere

November 6, 2012 in New York City. (Credit: Mike Coppola/Getty Images)

US-VOTE-2012-ELECTION-ROMNEY

US Presidential candidate Mitt Romney and his wife Ann Romney wave to supporters as they are joined by their family on election night November 7, 2012 in Boston Massachusetts. Romney conceded the race to US President Barack Obama. Ann Romney is at left. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)

during Mitt Romney's campaign election night event at the Boston Convention & Exhibition Center on November 7, 2012 in Boston, Massachusetts. After voters went to the polls in the heavily contested presidential race, networks projected incumbent U.S. President Barack Obama has won re-election against Republican candidate, former Massachusetts Gov. Mitt Romney. (Credit: Justin Sullivan/Getty Images)

Obama Campaigns In Richmond And Cleveland On Second Day Of Campaign Tour

U.S. President Barack Obama greets supporters during a campaign rally at Byrd Park October 25, 2012 in Richmond, Virginia. With less than two weeks to go before Election Day, Obama and his GOP opponent former Massachusetts Gov. Mitt Romney are criss crossing the country attempting to sway voters in all-important swing states. (Credit: Chip Somodevilla/Getty Images)

Obama Campaigns In Richmond And Cleveland On Second Day Of Campaign Tour

U.S. President Barack Obama greets supporters during a campaign rally at Byrd Park October 25, 2012 in Richmond, Virginia. With less than two weeks to go before Election Day, Obama and his GOP opponent former Massachusetts Gov. Mitt Romney are criss crossing the country attempting to sway voters in all-important swing states. (Credit: Chip Somodevilla/Getty Images)

Campaign 2012

US President Barack Obama (R) raises arms with Senator Mark Warner, D-VA, at the end of a campaign rally at The Carillon at Byrd Park on October 25, 2012 in Richmond, Virginia. (Credit: MANDEL NGAN/AFP/Getty Images)

US Republican Presidential candidate Mitt Romney makes a campaign stop at Jet Machine in Cincinnati, Ohio, October 25, 2012. Romney is on a daylong swing through three Ohio towns Thursday, sharpening his focus on a state that is critical to his hopes of winning the White House. (Credit: EMMANUEL DUNAND/AFP/Getty Images)

Campaign 2012

US President Barack Obama holds a baby while greeting supporters during a campaign rally at Ybor City Museum State Park on October 25, 2012 in Tampa, Florida. Obama returns to his home turf of Chicago, to cast an early ballot for the November 6 election, a brief detour during his eight-state, 40-hour campaign tour. (Credit: MANDEL NGAN/AFP/Getty Images)

US President Barack Obama shows a copy of his jobs plan as he speaks during a campaign rally at the Delray Beach Tennis Club, October 23, 2012 in Delray Beach, Florida. Barack Obama and Mitt Romney took their head-to-head battle for the US presidency to key swing states Tuesday after a feisty but inconclusive final debate. Post debate polling showed Obama winning Monday night's faceoff but analysts said Romney, who adopted more dovish-sounding foreign policy prescriptions that differed little from the president's, may have been helped by the encounter. "The fact that Mr Romney was able to show himself to not be the dangerous, wild conservative that Obama has been trying to portray him as, that may help him," said Christopher Arterton, a political science professor at George Washington University. (Credit: MANDEL NGAN/AFP/Getty Images)

Obama And Romney Spar In Final Debate Before Presidential Election

US President Barack Obama and Republican Presidential candidate Mitt Romney greet at the end of the third and final presidential debate at Lynn University in Boca Raton, Florida, October 22, 2012. (Credit: EMMANUEL DUNAND/AFP/Getty Images)

Obama And Romney Spar In Final Debate Before Presidential Election

U.S. President Barack Obama (R) debates with Republican presidential candidate Mitt Romney at the Keith C. and Elaine Johnson Wold Performing Arts Center at Lynn University on October 22, 2012 in Boca Raton, Florida. The focus for the final presidential debate before Election Day on November 6 is foreign policy. (Credit: Marc Serota/Getty Images)

Obama And Romney Spar In Final Debate Before Presidential Election

A combo picture shows the US President Barack Obama (R) and Republican presidential candidate Mitt Romney participate at the third and final presidential debate at Lynn University in Boca Raton, Florida, on October 22, 2012. The showdown focusing on foreign policy is being held in the critical toss-up state of Florida just 15 days before the election and promises to be among the most watched 90 minutes of the entire 2012 campaign. (Credit: JEWEL SAMAD/AFP/Getty Images)

Obama And Romney Spar In Final Debate Before Presidential Election

BOCA RATON, FL - OCTOBER 22: U.S. President Barack Obama (R) debates with Republican presidential candidate Mitt Romney at the Keith C. and Elaine Johnson Wold Performing Arts Center at Lynn University on October 22, 2012 in Boca Raton, Florida. The focus for the final presidential debate before Election Day on November 6 is foreign policy. (Credit: Rick Wilking-Pool/Getty Images)

Obama And Romney Spar In Final Debate Before Presidential Election

U.S. President Barack Obama (R) debates with Republican presidential candidate Mitt Romney at the Keith C. and Elaine Johnson Wold Performing Arts Center at Lynn University on October 22, 2012 in Boca Raton, Florida. The focus for the final presidential debate before Election Day on November 6 is foreign policy. (Credit: Joe Raedle/Getty Images)

Obama And Romney Spar In Final Debate Before Presidential Election

BOCA RATON, FL - OCTOBER 22: U.S. President Barack Obama (L) debates with Republican presidential candidate Mitt Romney at the Keith C. and Elaine Johnson Wold Performing Arts Center at Lynn University on October 22, 2012 in Boca Raton, Florida. The focus for the final presidential debate before Election Day on November 6 is foreign policy. (Credit: Michael Reynolds-Pool/Getty Images)

Obama And Romney Spar In Final Debate Before Presidential Election

U.S. President Barack Obama (R) debates with Republican presidential candidate Mitt Romney at the Keith C. and Elaine Johnson Wold Performing Arts Center at Lynn University on October 22, 2012 in Boca Raton, Florida. The focus for the final presidential debate before Election Day on November 6 is foreign policy. (Credit: Joe Raedle/Getty Images)

Obama And Romney Spar In Final Debate Before Presidential Election

U.S. President Barack Obama (R) debates with Republican presidential candidate Mitt Romney at the Keith C. and Elaine Johnson Wold Performing Arts Center at Lynn University on October 22, 2012 in Boca Raton, Florida. The focus for the final presidential debate before Election Day on November 6 is foreign policy. (Credit: Joe Raedle/Getty Images)

Obama And Romney Spar In Final Debate Before Presidential Election

U.S. President Barack Obama (R) debates with Republican presidential candidate Mitt Romney at the Keith C. and Elaine Johnson Wold Performing Arts Center at Lynn University on October 22, 2012 in Boca Raton, Florida. The focus for the final presidential debate before Election Day on November 6 is foreign policy. (Credit: Marc Serota/Getty Images)

Obama And Romney Spar In Final Debate Before Presidential Election

U.S. President Barack Obama (R) debates with Republican presidential candidate Mitt Romney at the Keith C. and Elaine Johnson Wold Performing Arts Center at Lynn University on October 22, 2012 in Boca Raton, Florida. The focus for the final presidential debate before Election Day on November 6 is foreign policy. (Credit: Win McNamee/Getty Images)

Obama And Romney Spar In Final Debate Before Presidential Election

A combo image shows (top) the US President Barack Obama debating with Republican presidential candidate Mitt Romney (down) on October 22, 2012 during the third presidential debate at Lynn University in Boca Raton, Florida. The final debate before the November 6 election is focusing on foreign policy. (Credit: JEWEL SAMAD/AFP/Getty Images)

President Obama Departs The White House En Route To Iowa

U.S. President Barack Obama walks across the South Lawn before boarding Marine One and departing the White House October 17, 2012 in Washington, DC. On the day after his second debate against his Republican rival, former Massachusetts Gov. Mitt Romney, Obama is traveling to Iowa and Ohio to campaign. (Credit: Chip Somodevilla/Getty Images)

President Obama Departs The White House En Route To Iowa

U.S. President Barack Obama walks across the South Lawn before boarding Marine One and departing the White House October 17, 2012 in Washington, DC. On the day after his second debate against his Republican rival, former Massachusetts Gov. Mitt Romney, Obama is traveling to Iowa and Ohio to campaign. (Credit: Chip Somodevilla/Getty Images)

US-VOTE-2012-DEBATE

US President Barack Obama (L) and Republican presidential candidate Mitt Romney (R) arrive on stage for the second presidential debate at Hofstra University on October 16, 2012 in Hempstead, New York, moderated by Candy Crowley of CNN (C). (Credit: POOL/AFP/Getty Images)

US-VOTE-2012-DEBATE

Journalist Candy Crowley prepares to moderate President Barack Obama and Republican Presidential candidate Mitt Romney participating in the second presidential debate at Hofstra University in Hempstead, New York, October 16, 2012. Obama and Romney face off in a town-hall style debate with undecided voters asking questions of the two candidates. (Credit: EMMANUEL DUNAND/AFP/Getty Images)

Barack Obama And Mitt Romney Participate In Second Presidential Debate

Republican Presidential Candidate Mitt Romney ( ) and President Barack Obama ( ) answer questions during a town hall style debate at Hofstra University October 16, 2012 in Hempstead, New York. During the second of three presidential debates, the candidates fielded questions from audience members on a wide variety of issues. (Credit: Pool/Getty Images)

US-VOTE-2012-DEBATE

Republican presidential candidate Mitt Romney speaks during the second presidential debate with US President Barack Obama October 16, 2012 at the David Mack Center at Hofstra University in Hempstead, New York. (Credit: MANDEL NGAN/AFP/Getty Images)

US-VOTE-2012-DEBATE

US President Barack Obama (L) Republican presidential candidate Mitt Romney (R) participate in the second presidential debate at the David Mack Center at Hofstra University in Hempstead, New York, October 16, 2012, moderated by CNN's Candy Crowley. (Credit: SAUL LOEB/AFP/Getty Images)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and Republican presidential candidate Mitt Romney (L) shake hands following the second presidential debate at the David Mack Center at Hofstra University in Hempstead, New York, October 16, 2012, moderated by CNN's Candy Crowley. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)

Barack Obama And Mitt Romney Participate In Second Presidential Debate

Republican presidential candidate Mitt Romney ( ) and U.S. President Barack Obama ( ) answer questions during a town hall style debate at Hofstra University October 16, 2012 in Hempstead, New York. During the second of three presidential debates, the candidates fielded questions from audience members on a wide variety of issues. (Credit: Bruce Bennett/Getty Images)

US-VOTE-2012-DEBATE

Republican Presidential candidate Mitt Romney kisses his wife Ann on October 16, 2012 at the end of the second presidential debate at Hofstra University in Hempstead, New York. (Credit: MANDEL NGAN/AFP/Getty Images)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and Republican presidential candidate Mitt Romney (L) participate in the second presidential debate, the only held in a townhall format, at the David Mack Center at Hofstra University in Hempstead, New York, October 16, 2012, moderated by CNN's Candy Crowley. (Credit: SAUL LOEB/AFP/Getty Images)

US-VOTE-2012-DEBATE

US President Barack Obama (L) and Republican presidential candidate Mitt Romney (R) participate in the second presidential debate, the only held in a townhall format, at the David Mack Center at Hofstra University in Hempstead, New York, October 16, 2012, moderated by CNN's Candy Crowley. (credit: SAUL LOEB/AFP/Getty Images)

US-VOTE-2012-DEBATE

US President Barack Obama and Republican presidential candidate Mitt Romney both speak at the same time during the second presidential debate October 16, 2012 at the David Mack Center at Hofstra University in Hempstead, New York. (Credit: MANDEL NGAN/AFP/Getty Images)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and Republican presidential candidate Mitt Romney (L) participate in the second presidential debate, the only held in a townhall format, at the David Mack Center at Hofstra University in Hempstead, New York, October 16, 2012, moderated by CNN's Candy Crowley. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)

US-VOTE-2012-DEBATE

CNN's Candy Crowley (C) conducts the second presidential debate with US President Barack Obama (R) and Republican presidential candidate Mitt Romney (L) at the David Mack Center at Hofstra University in Hempstead, New York, October 16, 2012. (Credit: SAUL LOEB/AFP/Getty Images)

US-VOTE-2012-DEBATE

Republican Presidential nominee Mitt Romney speaks on October 16, 2012 during the second of three presidential debates at Hofstra University in Hempstead, New York. (Credit: STAN HONDA/AFP/Getty Images)

US-VOTE-2012-DEBATE

Republican Presidential nominee Mitt Romney (L) and US President Barack Obama debate on October 16, 2012 during the second of three presidential debates at Hofstra University in Hempstead, New York. (Credit: TIMOTHY A. CLARY/AFP/Getty Images)

US-VOTE-2012-DEBATE

US President Barack Obama greets Republican presidential candidate Mitt Romney October 16, 2012 as the candidates arrive on stage for the second presidential debate at the David Mack Center at Hofstra University in Hempstead, New York. (Credit: MANDEL NGAN/AFP/Getty Images)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and Republican presidential candidate Mitt Romney (L) participate in the second presidential debate, the only held in a townhall format, at the David Mack Center at Hofstra University in Hempstead, New York, October 16, 2012, moderated by CNN's Candy Crowley. (Credit: SAUL LOEB/AFP/Getty Images)

US-VOTE-2012-DEBATE

US President Barack Obama arrives October 16, 2012 for the second presidential debate at the David Mack Center at Hofstra University in Hempstead, New York. (Credit: MANDEL NGAN/AFP/Getty Images)

A combination picture shows the US Vice President Joe Biden's reactions during his vice presidential debate with Republican vice presidential candidate Paul Ryan at the Norton Center at Centre College in Danville, Kentucky, October 11, 2012, moderated by Martha Raddatz of ABC News. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

A combination picture of the vice presidential debate between US Vice President Joe Biden (L) and Republican vice presidential candidate Paul Ryan (R) at the Norton Center at Centre College in Danville, Kentucky, October 11, 2012, moderated by Martha Raddatz of ABC News. (Credit: SAUL LOEB/AFP/GettyImages)

US President Barack Obama (R) speaks during his debate with Republican Presidential candidate Mitt Romney (L), who greets the audience at the conclusion in Denver, Colorado, on October 3, 2012. (Credit: STF/AFP/GettyImages)

US-VOTE-2012-DEBATE

Republican presidential candidate Mitt Romney speaks during his debate with US President Barack Obama at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney go head-to-head in their debut debate. (Credit: NICHOLAS KAMM/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama speaks during his debate with Republican Presidential candidate Mitt Romney at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney go head-to-head in their debut debate. (Credit: NICHOLAS KAMM/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and Republican challenger Mitt Romney (L) participate in their first debate at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney went head-to-head in their debut debate. (Credit: NICHOLAS KAMM/AFP/GettyImages)

US-VOTE-2012-DEBATE

Republican presidential candidate Mitt Romney speaks to moderator Jim Lehrer during his debate with US President Barack Obama at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney go head-to-head in their debut debate. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and Republican challenger Mitt Romney (L) participate in their first debate at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney went head-to-head in their debut debate. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and Republican challenger Mitt Romney shake hands following their first debate at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney went head-to-head in their debut debate. (Credit: NICHOLAS KAMM/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama (2n-L) and First Lady Michelle Obama (L) join Republican Presidential candidate Mitt Romney (2nd-R) and his family at the conclusion of the first presidential debate on October 3, 2012 in Denver, Colorado. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama (top) speaks during his debate with Republican Presidential candidate Mitt Romney (bottom) at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney go head-to-head in their debut debate. (Credit: NICHOLAS KAMM/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and Republican presidential candidate Mitt Romney (L) arrive for the first presidential debate at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney went head-to-head in their debut debate. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama and Republican presidential candidate Mitt Romney look down October 3, 2012 during the first presidential debate at the University of Denver in Denver, Colorado. (Credit: MANDEL NGAN/AFP/GettyImages)

US-VOTE-2012-DEBATE

Republican presidential candidate Mitt Romney stands with his wife Ann and family following the first presidential debate with US President Barack Obama at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney went head-to-head in their debut debate. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

Republican presidential candidate Mitt Romney hugs one of his grandchildren as Ann Romney watches at the conclusion of the first presidential debate in Denver, Colorado, October 3, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama and Republican presidential candidate Mitt Romney walk towards their wifes October 3, 2012 at the conclusion of the first presidential debate at the University of Denver in Denver, Colorado. (Credit: MANDEL NGAN/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama (R) greets Republican presidential candidate Mitt Romney (L) following the first presidential debate at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney went head-to-head in their debut debate. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama and Republican presidential candidate Mitt Romney share a laugh October 3, 2012 at the conclusion of the first presidential debate at the University of Denver in Denver, Colorado.(Credit: MANDEL NGAN/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama speaks during his debate with Republican Presidential candidate Mitt Romney at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney go head-to-head in their debut debate. (Credit: NICHOLAS KAMM/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and Republican presidential candidate Mitt Romney (L) participate in the first presidential debate at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012, moderated by Jim Lehrer (C) of the PBS NewsHour. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney go head-to-head in their debut debate. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and Republican presidential candidate Mitt Romney (L) participate in the first presidential debate at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012, moderated by Jim Lehrer (C) of the PBS NewsHour. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney go head-to-head in their debut debate. (Credit:SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and Republican presidential candidate Mitt Romney (L) participate in the first presidential debate at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012, moderated by Jim Lehrer (C) of the PBS NewsHour. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney go head-to-head in their debut debate. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama (R) and republican Presidential candidate Mitt Romney (L) participate in the first presidential debate at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012, moderated by Jim Lehrer (C) of the PBS NewsHour. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney go head-to-head in their debut debate. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEBATE

US President Barack Obama and Republican presidential candidate Mitt Romney wave October 3, 2012 after shaking hands as he arrives on stage for the first presidential debate at the University of Denver in Denver, Colorado. (Credit: MANDEL NGAN/AFP/GettyImages)

US-VOTE-2012-DEBATE-OBAMA-ROMNEY-COMBO

In this image combination, Republican presidential candidate Mitt Romney (L) and US President Barack Obama debate at Magness Arena at the University of Denver in Denver, Colorado, October 3, 2012. After hundreds of campaign stops, $500 million in mostly negative ads and countless tit-for-tat attacks, Obama and Romney go head-to-head in their debut debate. (Credit: SAUL LOEB/AFP/GettyImages)

MIAMI, FL - SEPTEMBER 27: Florida Democratic congressional candidate Joe Garcia (R) speaks with voters as he continues his campaign against his opponent Rep. David Rivera (R-FL) on September 27, 2012 in Miami, Florida. It has been reported that the campaign of Garcia's Democratic primary opponent, Justin Lamar Sternad, may have been funded by Rivera. Reports indicate that the FBI is looking to speak to Sternad's currently missing campaign manager, Ana Sol Alliegro, who, it is alleged, acted as a liaison between Sternad's campaign and Rivera. (Credit: Joe Raedle/Getty Images)

Romney Attends Campaign Rally At American Legion Post In Virginia

SPRINGFIELD, VA - SEPTEMBER 27: Republican U.S. presidential candidate and former Massachusetts Governor Mitt Romney speaks during a Veterans for Romney event at American Legion Post 176 September 27, 2012 in Springfield, Virginia. Romney continued to campaign for his run for the White House in the battleground state of Virginia. (Credit: Alex Wong/Getty Images)

US Republican presidential candidate Mitt Romney signs autographs after speaking at a campaign event in Springfield, Virginia, on September 27, 2012. A flurry of polls showing widening leads for President Barack Obama Wednesday heaped pressure on Mitt Romney to use their first head-to-head debate next week to launch a major comeback bid. Fresh surveys showed Obama cementing his advantage in the key state battlegrounds that will decide the US election on November 6, and putting clear distance between himself and his Republican challenger nationwide. (Credit: JEWEL SAMAD/AFP/GettyImages)

US-VOTE-2012-REPUBLICAN CAMPAIGN-ROMNEY

US Republican presidential candidate Mitt Romney speaks at "Veterans for Romney" campaign event in Springfield, Virginia, on September 27, 2012. A flurry of polls showing widening leads for President Barack Obama Wednesday heaped pressure on Mitt Romney to use their first head-to-head debate next week to launch a major comeback bid. Fresh surveys showed Obama cementing his advantage in the key state battlegrounds that will decide the US election on November 6, and putting clear distance between himself and his Republican challenger nationwide. (Credit: JEWEL SAMAD/AFP/GettyImages)

US-VOTE-2012-DEMOCRATIC CAMPAIGN

US President Barack Obama greets supporters before speaking during a campaign event at Farm Bureau Live in Virginia Beach, Virginia, September 27, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

US-VOTE-2012-DEMOCRATIC CAMPAIGN

US President Barack Obama greets wellwishers upon arrival on Air Force One at Naval Air Station Oceania in Virginia Beach, Virginia, September 27, 2012, as he travels to campaign events. (Credit: SAUL LOEB/AFP/GettyImages)

Early Voting Begins In Iowa For Presidential Election

WATERLOO, IA - SEPTEMBER 27: Betty Carlson (L) helps her husband Keith Carlson, who is visually impaired, fill out his ballot during early voting at the Black Hawk County Courthouse on September 27, 2012 in Waterloo, Iowa. Early voting starts today in Iowa where in the 2008 election 36 percent of voters cast an early ballot. (Credit: Scott Olson/Getty Images)

US President Barack Obama greets supporters after speaking at a campaign rally at the Kent State University on September 26, 2012 in Kent, Ohio. Obama and Romney clashed on trade with China, the giant Asian economy, at dueling political events in Ohio, a key midwestern swing state which has seen thousands of blue collar jobs migrate to low cost economies abroad, including China. (Credit:JEWEL SAMAD/AFP/GettyImages)

US-VOTE-2012-DEMOCRATIC CAMPAIGN-OBAMA

US President Barack Obama waves at supporters after speaking at a campaign rally at the Kent State University on September 26, 2012 in Kent, Ohio. Obama and Romney clashed on trade with China, the giant Asian economy, at dueling political events in Ohio, a key midwestern swing state which has seen thousands of blue collar jobs migrate to low cost economies abroad, including China. (Credit: JEWEL SAMAD/AFP/GettyImages)

US President Barack Obama speaks during a campaign rally at the Kent State University on September 26, 2012 in Kent, Ohio. Obama and Romney clashed on trade with China, the giant Asian economy, at dueling political events in Ohio, a key midwestern swing state which has seen thousands of blue collar jobs migrate to low cost economies abroad, including China. (Credit: JEWEL SAMAD/AFP/GettyImages)

Bowling Green, OH - September 26: U.S. President Barack Obama speaks to supporters at the Stroh Center on September 26, 2012 in Bowling Green, Ohio. Six days before early voting starts in Ohio, the President discussed what he says is a real and achievable plan to restore middle-class economic security by paying down the debt in a balanced way. (Credit: J.D. Pooley/Getty Images)

Romney Takes Whirlwind Campaign Tour Of Ohio

WESTERVILLE, OH - SEPTEMBER 26: Supporters hold up signs during a campaign rally of Republican U.S. presidential candidate Mitt Romney at Westerville South High School September 26, 2012 in Westerville, Ohio. Romney continued his two-day âRomney Plan For A Stronger Middle Classâ bus tour in the state of Ohio. (Credit: Alex Wong/Getty Images)

Bradley Thompson (L) kneels down to propose to Laura Bowman (R), who accepted, on the stage at the Tampa Bay Times Forum in Tampa, Florida, on August 29, 2012 during the Republican National Convention. Thompson is production manager and Bowman is a production coordinator for the convention. (Credit: STAN HONDA/AFP/GettyImages)

Republican National Convention

(Credit: MLADEN ANTONOV/AFP/GettyImages)

Republican National Convention

New Jersey Governor Chris Christie speaks at the Tampa Bay Times Forum in Tampa, Florida, on August 28, 2012 during the Republican National Convention. (Credit: STAN HONDA/AFP/GettyImages)

Republican National Convention

A giant screen shows the Governor of New Jersey Christopher James "Chris" Christie adresses the crowd of supporters at the Tampa Bay Times Forum in Tampa, Florida, on August 28, 2012 during the Republican National Convention. The 2012 Republican National Convention is expected to host 2,286 delegates and 2,125 alternate delegates from all 50 states, the District of Columbia and five territories. (Credit: MLADEN ANTONOV/AFP/GettyImages)

Republican National Convention

US Republican presidential candidate Mitt Romney and his wife Ann wave after her speech during Republican National Convention (RNC) at the Tampa Bay Times Forum in Tampa, Florida, on August 28, 2012. Mitt Romney wrapped up the Republican presidential nomination on Tuesday as wife Ann prepared to sell their family values and personal love story to US voters in a prime-time convention speech. (Credit: JEWEL SAMAD/AFP/GettyImages)

Republican National Convention

US Republican presidential candidate Mitt Romney's wife Ann speaks during Republican National Convention (RNC) at the Tampa Bay Times Forum in Tampa, Florida, on August 28, 2012. Mitt Romney wrapped up the Republican presidential nomination on Tuesday as wife Ann prepared to sell their family values and personal love story to US voters in a prime-time convention speech. (Credit: JEWEL SAMAD/AFP/GettyImages)

Republican National Convention

Ann, wife of Republican presidential candidate Mitt Romney, addresses the crowd at the Tampa Bay Times Forum in Tampa, Florida, on August 28, 2012 during the Republican National Convention. (Credit: STAN HONDA/AFP/GettyImages)

Republican National Convention

US Republican presidential candidate Mitt Romney (L) speaks with former US secretary of state Condoleezza Rice during the Republican National Convention (RNC) at the Tampa Bay Times Forum in Tampa, Florida, on August 28, 2012. Romney's image will get a carefully scripted makeover during the convention as the Republican White House hopeful aims to close the yawning likability gap between himself and President Barack Obama. (Credit: JEWEL SAMAD/AFP/GettyImages)

Republican National Convention

During the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Mark Wilson/Getty Images)

Republican National Convention

During the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Spencer Platt/Getty Images)

Republican National Convention

During the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Mark Wilson/Getty Images)

Republican National Convention

During the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Mark Wilson/Getty Images)

Republican National Convention

Former Republican presidential candidate Newt Gingrich is surrounded by media at the Tampa Bay Times Forum in Tampa, Florida, on August 28, 2012 during the Republican National Convention. The 2012 Republican National Convention is expected to host 2,286 delegates and 2,125 alternate delegates from all 50 states, the District of Columbia and five territories. (Credit: ROBYN BECK/AFP/GettyImages)

Republican National Convention

During the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Spencer Platt/Getty Images)

Republican National Convention

During the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Chip Somodevilla/Getty Images)

Republican National Convention

During the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Spencer Platt/Getty Images)

Republican National Convention

During the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Mark Wilson/Getty Images)

Republican National Convention

During the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Scott Olson/Getty Images)

Campaign 2012

US President Barack Obama speaks during a campaign event at Colorado State University in Fort Collins, Colorado, August 28, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

US President Barack Obama greets supporters during a campaign event at Colorado State University in Fort Collins, Colorado, August 28, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

Protesters Demonstrate During The Republican National Convention

TAMPA, FL - AUGUST 28: Protesters march during the National Republican Convention on August 28, 2012 in Tampa, Florida. Several marches took place during the day are expected to continue throughout the convention. The group was lead along a predetermined route and the march ended near a small group from Westboro Baptist Church when law enforcement officials intervened and prevented any violence. (Credit: Edward Linsmier/Getty Images)

Republican National Convention

Janine Turne during the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Mark Wilson/Getty Images)

Republican National Convention

Mia Love during the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Mark Wilson/Getty Images)

Republican National Convention

During the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit:Chip Somodevilla/Getty Images)

Republican National Convention

John Boehner during the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Win McNamee/Getty Images)

Republican National Convention

Scott Romney, brother of Republican presidential candidate Mitt Romney, pumps his fist after reading down the votes for the state of Michigan during the roll call for nomination of president of the United States at the Tampa Bay Times Forum in Tampa, Florida, on August 28, 2012 during the Republican National Convention. The 2012 Republican National Convention is expected to host 2,286 delegates and 2,125 alternate delegates from all 50 states, the District of Columbia and five territories. (Credit: BRENDAN SMIALOWSKI/AFP/GettyImages)

Republican National Convention

During the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Spencer Platt/Getty Images)

Republican National Convention

Mitch McConnell during the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Mark Wilson/Getty Images)

Republican National Convention

Richard Snyder and Scott Romney during the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Credit: Chip Somodevilla/Getty Images)

Obama Rallies Young Voters At Iowa State University

AMES, IA - AUGUST 28: Iowa Senator Tom Harkin (D) takes the stage before an address by President Barrack Obama on the campus of Iowa State University on August 28, 2012 in Ames, Iowa. ISU was the first stop on a three campus college tour where the President was addressing mainly students about education finance and healthcare. (Credit: David Greedy/Getty Images)

Obama Wraps Up College Campaign Tour In Virginia

CHARLOTTESVILLE, VA - AUGUST 29: A vendor sells campaign buttons outside an Obama campaign event August 29, 2012 in Charlottesville, Virginia. U.S. President Barack Obama continued to campaign for his re-election on the second and last day of his college tour through Iowa and Virginia. (Credit: Alex Wong/Getty Images)

Campaign 2012

US Republican presidential candidate and former Massachusetts Governor Mitt Romney greets coal miners after speaking during a campaign event at the American Energy Corporation in Beallsville, Ohio, August 14, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

US President Barack Obama delivers remarks during a campaign event in Leesburg, VA, August 2, 2012. (Credit: JIM WATSON/AFP/GettyImages)

Campaign 2012

US President Barack Obama delivers remarks during a campaign event in Leesburg, VA, August 2, 2012. (Credit: JIM WATSON/AFP/GettyImages)

US President Barack Obama (C) shakes hands with members of the Presidential Logistics Squadron who oversaw maintence on Air Force One before boarding the plane at Andrews Air Force Base in Maryland on August 6, 2012. Obama is traveling to Connecticut to attend campaign events. (Credit: JIM WATSON/AFP/GettyImages)

Campaign 2012

US President Barack Obama delivers remarks during a campaign event in Stamford, Connecticut, on August 6, 2012. (Credit: JIM WATSON/AFP/GettyImages)

Mitt Romney Campaigns In Chicagoland Area

CHICAGO, IL - AUGUST 07: Republican presidential candidate and former Massachusetts Gov. Mitt Romney chats with Dutchie Caray, the widow of legendary Chicago Cubs ' announcer Harry Caray, following a fundraiser at Harry Caray's Italian Steakhouse and Bar on August 7, 2012 in Chicago, Illinois. The event was the first of two fundraisers Romney is scheduled to attend today in Chicago. (Credit: Scott Olson/Getty Images)

Mitt Romney Campaigns In Des Moines

DES MOINES, IA - AUGUST 08: Republican presidential candidate and former Massachusetts Gov. Mitt Romney speaks during a campaign event at Central Campus High School on August 8, 2012 in Des Moines, Iowa. Mitt Romney is campaigning in Iowa before traveling to New Jersey and New York for fundraising events. (Credit: Justin Sullivan/Getty Images)

Campaign 2012

DES MOINES, IA - AUGUST 08: Republican presidential candidate and former Massachusetts Gov. Mitt Romney speaks during a campaign event at Central Campus High School on August 8, 2012 in Des Moines, Iowa. Mitt Romney is campaigning in Iowa before traveling to New Jersey and New York for fundraising events. (Credit: Justin Sullivan/Getty Images)

Campaign 2012

US President Barack Obama waves from Marine One prior to departing from the South Lawn of the White House in Washington, DC, August 8, 2012. Obama is traveling on a 2-day trip to Colorado for campaign events. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

Republican presidential candidate and former Massachusetts Gov. Mitt Romney speaks during a campaign event at Central Campus High School on August 8, 2012 in Des Moines, Iowa. Mitt Romney is campaigning in Iowa before traveling to New Jersey and New York for fundraising events. (Credit: Justin Sullivan/Getty Images)

DENVER, CO - AUGUST 8: U.S. President Barack Obama speaks during a grassroots campaign stop at the Auraria Events Center August 8, 2012 in Denver, Colorado. Obama spoke mainly about his vision for the economy and how he says Obamacare has helped women and their access to healthcare. (Credit: Marc Piscotty/Getty Images)

Campaign 2012

Supporters listens as US President Barack Obama delivers remarks during a campaign event at Grand Junction High School in Grand Junction, Colorado, August 8, 2012. (Credit: JIM WATSON/AFP/GettyImages)

Republican Candidate For Presidential Mitt Romney Attends Fundraising Events In New York Area

August 9, 2012 in New York City. (Credit:Mario Tama/Getty Images)

Campaign 2012

US President Barack Obama (R) shakes hands with supporters after delivering remarks during a campaign event at the Colorado State Fair grounds in Pueblo, Colorado, August 9, 2012. (Credit: JIM WATSON/AFP/GettyImages)

Campaign 2012

Women listen as US President Barack Obama delivers remarks during a campaign event at the Colorado State Fair grounds in Pueblo, Colorado, August 9, 2012. (Credit: JIM WATSON/AFP/GettyImages)

Obama Takes Two-Day Campaign Swing Through Colorado

DENVER, CO - AUGUST 9: U.S. President Barack Obama speaks during a campaign stop at the Palace of Agriculture on the Colorado State Fairgrounds August 9, 2012 in Pueblo, Colorado. Obama covered a number of topics including paying down our debt in a balanced way, job growth and creation and preventing a scheduled tax increase. (Credit: Marc Piscotty/Getty Images)

Obama Takes Two-Day Campaign Swing Through Colorado

DENVER, CO - AUGUST 9: The crowd of about 3,500 people as U.S. President Barack Obama spoke during a grassroots campaign stop at the Palace of Agriculture on the Colorado State Fairgrounds August 9, 2012 in Pueblo, Colorado. Obama covered a number of topics including paying down our debt in a balanced way, job growth and creation and preventing a scheduled tax increase on 98 percent of Americans. (Credit: Marc Piscotty/Getty Images)

Campaign 2012

US President Barack Obama delivers remarks during a campaign event at Colorado College in Colorado Springs, Colorado, August 9, 2012. (Credit: JIM WATSON/AFP/GettyImages)

Campaign 2012

Elementary school teacher Christy Howard is hugged by US President Barack Obama as he arrives to delivers remarks during a campaign event at Colorado College in Colorado Springs, Colorado, August 9, 2012. (Credit: JIM WATSON/AFP/GettyImages)

Campaign 2012

Wisconsin Representative Paul Ryan waves alongside his children after US Republican presidential candidate and former Massachusetts Governor Mitt Romney named Ryan as his vice presidential running mate during a campaign rally at the Nauticus Museum after touring the USS Wisconsin in Norfolk, Virginia, August 11, 2012. Romney and his new running mate embark on the first day of a 4-day bus trip that will take the White House hopefuls to 4 key swing states, Virginia, North Carolina, Florida and Ohio. (Credit: SAUL LOEB/AFP/GettyImages)

ASHLAND, VA - AUGUST 11: Republican presidential candidate and former Massachusetts Gov. Mitt Romney purchases pies at Homemades by Suzanne during a campaign stop August 11, 2012 in Ashland, Virginia. Mitt Romney kicked off a four day bus tour with an announcement of his running mate, Rep. Paul Ryan (R-WI). (Credit: Justin Sullivan/Getty Images)

Campaign 2012

US President Barack Obama walks to Marine One on the South Lawn of the White House on August 11, 2012 in Washington. Obama is traveling to Chicago where he will attend fund raisers and campaign events prior to traveling to Iowa on Monday to begin a three day bus tour of the battle ground state during his reelection bid. (Credit: BRENDAN SMIALOWSKI/AFP/GettyImages)

US Republican presidential candidate and former Massachusetts Governor Mitt Romney waves from his campaign bus following a campaign rally at the NASCAR Technical Institute in Mooresville, North Carolina, August 12, 2012. Romney and his running mate Wisconsin Representative Paul Ryan continue on the second day of a 4-day bus trip that will take Romney to 4 key swing states, Virginia, North Carolina, Florida and Ohio, and also to Ryan's home state of Wisconsin. (Credit: SAUL LOEB/AFP/GettyImages)

Republican presidential candidate and former Massachusetts Governor Mitt Romney (R) and his running mate Rep. Paul Ryan (R-WI) during a campaign rally at the NASCAR Technical Institute on August 12, 2012 in Mooresville, North Carolina. Mitt Romney continues his four day bus tour a day after announcing his running mate, Rep. Paul Ryan (R-WI). (Credit: Justin Sullivan/Getty Images)

Republican presidential candidate and former Massachusetts Governor Mitt Romney (R) and his running mate Rep. Paul Ryan (R-WI) during a campaign rally at the NASCAR Technical Institute on August 12, 2012 in Mooresville, North Carolina. Mitt Romney continues his four day bus tour a day after announcing his running mate, Rep. Paul Ryan (R-WI). (Credit: Justin Sullivan/Getty Images)

Campaign 2012

US Republican Vice Presidential hopeful Wisconsin Representative Paul Ryan greets supporters prior to speaking with US Republican presidential candidate and former Massachusetts Governor Mitt Romney during a campaign rally at Absolute Style furniture company in High Point, North Carolina, August 12, 2012. Romney and Ryan continue on the second day of a 4-day bus trip that will take Romney to 4 key swing states, Virginia, North Carolina, Florida and Ohio, and also to Ryan's home state of Wisconsin. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

US President Barack Obama speaks at a campaign event in Chicago on August 12, 2012. Obama welcomed Paul Ryan into the US election, but warned the Republican vice presidential pick was an "articulate" spokesman for a vision he fundamentally opposes. (Credit: YURI GRIPAS/AFP/GettyImages)

Campaign 2012

US President Barack Obama waves at a campaign event in Chicago on August 12, 2012. Obama welcomed Paul Ryan into the US election, but warned the Republican vice presidential pick was an "articulate" spokesman for a vision he fundamentally opposes. (Credit: YURI GRIPAS/AFP/GettyImages)

In Profile: 100 Years In US Presidential Races

(FILE PHOTO) In this composite image a comparison has been made between US Presidential Candidates Barack Obama (L) and Mitt Romney. The November 6, 2012 elections will decide between Obama and Romney who will win to become the next President of the United States. ***LEFT IMAGE*** WEST PALM BEACH, FL - JULY 19: U.S. President Barack Obama delivers remarks to seniors at Century Village on July 19, 2012 in West Palm Beach, Florida. Obama is campaigning for two days in Florida, a crucial swing state in November's presidential election. (Photo by Marc Serota/Getty Images) ***RIGHT IMAGE*** GREEN BAY, WI - APRIL 02: Republican Presidential candidate, former Massachusetts Gov. Mitt Romney speaks during a town hall style meeting at Wisconsin Building Supply on April 2, 2012 in Green Bay, Wisconsin. With one day to go before the Wisconsin primary, Mitt Romney makes a final push through the state. (Credit: Justin Sullivan/Getty Images)

Obama Speaks At Fundraising Event In Chicago

US President Barack Obama speaks to supporters at the Bridgeport Arts Center in Chicago, Il during a fundraising event celebrating his birthday. (Credit:Pool)

Campaign 2012

US Republican vice presidential hopeful Wisconsin Representative Paul Ryan wipes tears from his eyes as he arrives for a campaign rally with presidential candidate and former Massachusetts Governor Mitt Romney at Waukesha County Expo Center in Waukesha, Wisconsin, on August 12, 2012. Romney and Ryan visit Ryan's home state on the second day of a four-day bus trip that will take Romney to four key swing states, Virginia, North Carolina, Florida and Ohio. (Credit: SAUL LOEB/AFP/GettyImages)

Republican presidential candidate and former Massachusetts Governor Mitt Romney (R) and his running mate Rep. Paul Ryan (R-WI) during a campaign rally at the Waukesha County Expo Center on August 12, 2012 in Waukesha, Wisconsin. Mitt Romney continues his four day bus tour a day after announcing his running mate, Rep. Paul Ryan (R-WI). (Credit: Justin Sullivan/Getty Images)

Campaign 2012

US Republican Vice Presidential hopeful Wisconsin Representative Paul Ryan's speech notes are seen on the podium as he greets supporters during a campaign rally at Waukesha County Expo Center in Waukesha, Wisconsin, August 12, 2012. Romney and Ryan visit Ryan's home state on the second day of a 4-day bus trip that will take Romney to 4 key swing states, Virginia, North Carolina, Florida and Ohio. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

Supporters cheer for US Republican presidential candidate and former Massachusetts Governor Mitt Romney and US Republican Vice Presidential hopeful Wisconsin Representative Paul Ryan during a campaign rally at Waukesha County Expo Center in Waukesha, Wisconsin, August 12, 2012. Romney and Ryan visit Ryan's home state on the second day of a 4-day bus trip that will take Romney to 4 key swing states, Virginia, North Carolina, Florida and Ohio. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

US Republican Vice Presidential hopeful Wisconsin Representative Paul Ryan greets supporters during a campaign rally at Waukesha County Expo Center in Waukesha, Wisconsin, August 12, 2012. Romney and Ryan visit Ryan's home state on the second day of a 4-day bus trip that will take Romney to 4 key swing states, Virginia, North Carolina, Florida and Ohio. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

Supporters cheer for US Republican presidential candidate and former Massachusetts Governor Mitt Romney and vice presidential hopeful Wisconsin Representative Paul Ryan during a campaign rally at Waukesha County Expo Center in Waukesha, Wisconsin, August 12, 2012. Romney and Ryan visit Ryan's home state on the second day of a 4-day bus trip that will take Romney to 4 key swing states, Virginia, North Carolina, Florida and Ohio. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

US Republican presidential candidate and former Massachusetts Governor Mitt Romney (L) shakes hands with his running mate Wisconsin Representative Paul Ryan in front of the campaign bus prior to each boarding their own campaign airplanes at General Mitchell Airport in Milwaukee, Wisconsin, August 12, 2012. Romney and Ryan continue on the second day of a 4-day bus trip that will take Romney to 4 key swing states, Virginia, North Carolina, Florida and Ohio, and also to Ryan's home state of Wisconsin. (Credit: SAUL LOEB/AFP/GettyImages)

US Republican presidential candidate and former Massachusetts Governor Mitt Romney greets supporters after speaking during a campaign rally at Flagler College in St. Augustine, Florida, August 13, 2012. Romney and his running mate Wisconsin Congressman Paul Ryan will take their re-energized presidential campaign to two key states on Monday, seeking to persuade voters that they can restore America's economic might. Romney campaigns in Florida while Ryan heads to Iowa, both battleground states which may decide the outcome of the November 6 presidential election. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

US Republican presidential candidate and former Massachusetts Governor Mitt Romney (L) shakes hands with Florida Governor Rick Scott during a campaign rally at Flagler College in St. Augustine, Florida, August 13, 2012. Romney and his running mate Wisconsin Congressman Paul Ryan will take their re-energized presidential campaign to two key states on Monday, seeking to persuade voters that they can restore America's economic might. Romney campaigns in Florida while Ryan heads to Iowa, both battleground states which may decide the outcome of the November 6 presidential election.(Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

US President Barack Obama waves as he departs from O'Hare International Airport in Chicago, Illinois en route Omaha, Nebraska on August 13, 2012. Obama headed back Monday to a key swing state that nurtured his White House dream, as Republican vice-presidential pick Paul Ryan tried to spoil the US president's political homecoming. Obama set off from his hometown of Chicago to embark on a three-day bus tour of the midwestern state of Iowa, the ground where he built his 2008 campaign juggernaut and will now use to showcase his economic credentials. (Credit: YURI GRIPAS/AFP/GettyImages)

Campaign 2012

US President Barack Obama is greeted by a military personnel as he arrives at at Offutt Air Force Base in Omaha, Nebraska on August 13, 2012. Obama headed back Monday to a key swing state that nurtured his White House dream, as Republican vice-presidential pick Paul Ryan tried to spoil the US president's political homecoming. Obama set off from his hometown of Chicago to embark on a three-day bus tour of the midwestern state of Iowa, the ground where he built his 2008 campaign juggernaut and will now use to showcase his economic credentials. The president will begin his tour aboard his sleek armored bus in Council Bluffs, Iowa, on the Nebraska border, and wend his way east, holding formal campaign events and stopping at cafes and diners along the way. (Credit: YURI GRIPAS/AFP/GettyImages)

Campaign 2012

Supporters cheer as US President Barack Obama delivers remarks during a campaign event at Bayliss Park in Council Bluffs, Iowa, August 13, 2012. Obama set off from his hometown of Chicago to embark on a three-day bus tour of the midwestern state of Iowa, the ground where he built his 2008 campaign juggernaut and will now use to showcase his economic credentials. The president will begin his tour aboard his sleek armored bus in Council Bluffs, Iowa and wend his way east, holding formal campaign events and stopping at cafes and diners along the way. (Credit: JIM WATSON/AFP/GettyImages)

Campaign 2012

US President Barack Obama (C) delivers remarks during a campaign event at Bayliss Park in Council Bluffs, Iowa, August 13, 2012. Obama set off from his hometown of Chicago Monday, to embark on a three-day bus tour of the midwestern state of Iowa, the ground where he built his 2008 campaign juggernaut and will now use to showcase his economic credentials. The president will begin his tour aboard his sleek armored bus in Council Bluffs, Iowa and wend his way east, holding formal campaign events and stopping at cafes and diners along the way. (Credit: JIM WATSON/AFP/GettyImages)

President Obama Kicks Off Three Day Bus Tour In Iowa

COUNCIL BLUFFS, IA - AUGUST 13: President Barack Obama arrives at a grassroots campaign stop at Bayliss Park, August 13, 2012, in Council Bluffs, Iowa. President Barack Obama kicked off a three-day bus tour of Iowa on a campaign trip through drought-stricken Iowa. (Credit: Julie Denesha/Getty Images)

President Obama Kicks Off Three Day Bus Tour In Iowa

COUNCIL BLUFFS, IA - AUGUST 13: Supporters hold signs as President Barack Obama urged Congress to pass the Farm Bill, during a grassroots campaign stop at Bayliss Park, August 13, 2012, in Council Bluffs, Iowa. President Barack Obama kicked off a three-day bus tour of Iowa on a campaign trip through drought-stricken Iowa. (Credit: Julie Denesha/Getty Images)

US Republican presidential candidate and former Massachusetts Governor Mitt Romney (L) stands alongside Florida Republican Senator Marco Rubio as he pretends to throw an orange to members of the press sitting at the back of the campaign plane while in flight from St. Augustine, Florida, to Miami for campaign events on August 13, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

US President Barack Obama (R) speaks with some young girls as he gets shaved ice at Tropical Sno in Denison, Iowa, on August 13, 2012 during his three-day campaign bus tour through Iowa. (Credit: JIM WATSON/AFP/GettyImages)

US Republican presidential candidate and former Massachusetts Governor Mitt Romney speaks during a campaign event at Palacio De Los Jugos in Miami, Florida, on August 13, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

US Republican presidential candidate and former Massachusetts Governor Mitt Romney speaks during a campaign event at Palacio De Los Jugos in Miami, Florida, on August 13, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

The speech notes of US Republican presidential candidate and former Massachusetts Governor Mitt Romney are seen on the podium after speaking during a campaign event at Palacio De Los Jugos in Miami, Florida, on August 13, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

A supporter (R) reacts after shaking hands with US President Barack Obama (L) as he works the rope line after delivering remarks during a campaign event at Herman Park in Boone, Iowa, on August 13, 2012. (Credit: JIM WATSON/AFP/GettyImages)

Campaign 2012

US Republican presidential candidate and former Massachusetts Governor Mitt Romney (L) waves alongside his son Craig prior to speaking during a campaign event at Palacio De Los Jugos in Miami, Florida, on August 13, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

Supporters of US Republican presidential candidate and former Massachusetts Governor Mitt Romney listen to him speak during a campaign event at Palacio De Los Jugos in Miami, Florida, on August 13, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

Campaign 2012

US President Barack Obama (L) and US Secretary of Agriculture Tom Vilsack (C) greet people as they visit the Iowa State Fair in Des Moines, Iowa, on August 13, 2012 during an unannounced stop on his three-day campaign bus tour. (Credit: JIM WATSON/AFP/GettyImages)

US President Barack Obama (L) talks with people as he visits the Coffee Connection in Knoxville, Iowa, August 14, 2012, during an unannounced stop on his three-day campaign bus tour. (Credit: JIM WATSON/AFP/GettyImages)

Campaign 2012

US President Barack Obama (C) is applauded as he arrives to deliver remarks during a campaign event at the Nelson Pioneer Farm & Museum in Oskaloosa, Iowa, August 14, 2012, during his three-day campaign bus tour. (Credit: JIM WATSON/AFP/GettyImages)

Campaign 2012

(Credit: JIM WATSON/AFP/GettyImages)

Campaign 2012

US Republican presidential candidate and former Massachusetts Governor Mitt Romney greets coal miners after speaking during a campaign event at the American Energy Corporation in Beallsville, Ohio, August 14, 2012. (Credit: SAUL LOEB/AFP/GettyImages)

Obama Holds Campaign Event At Virginia High School

ARLINGTON, VA - AUGUST 2: President Barack Obama holds a campaign rally at Loudoun County High School on August 2, 2012 in Leesburg, VA. Obama campaigned earlier in the day in Florida. (Credit: Brendan Hoffman/Getty Images) *** Local Caption *** Barack Obama

Obama Holds Campaign Event At Virginia High School

ARLINGTON, VA - AUGUST 2: President Barack Obama holds a campaign rally at Loudoun County High School on August 2, 2012 in Leesburg, VA. Obama campaigned earlier in the day in Florida. (Credit: Brendan Hoffman/Getty Images)

Obama Holds Campaign Event At Virginia High School

ARLINGTON, VA - AUGUST 2: President Barack Obama shakes hands with audience members at the end of a campaign rally at Loudoun County High School on August 2, 2012 in Leesburg, VA. Obama campaigned earlier in the day in Florida. (Credit: Brendan Hoffman/Getty Images)

US President Barack Obama greets supporters upon arrival at Manchester-Boston Regional Airport in Manchester, New Hampshire, on August 18, 2012. Obama is in New Hampshire to attend campaign events. (Credit: NICHOLAS KAMM/AFP/GettyImages)

Paul Ryan Attends Victory Rally In Florida

THE VILLAGES, FL - AUGUST 18: Republican Vice Presidential candidate, U.S. Rep. Paul Ryan (R-WI) greets supporters during the Victory Rally in Florida at Town Square, Lake Sumter Landing on August 18, 2012 in The Villages, Florida. Ryan spoke about his family's reliance on Medicare. (Credit: Gerardo Mora/Getty Images)

Paul Ryan Attends Victory Rally In Florida

THE VILLAGES, FL - AUGUST 18: People listen as Republican Vice Presidential candidate, U.S. Rep. Paul Ryan (R-WI) speaks during the Victory Rally in Florida at Town Square, Lake Sumter Landing on August 18, 2012 in The Villages, Florida. Ryan spoke about his family's reliance on Medicare. (Credit: Gerardo Mora/Getty Images)

Campaign 2012

US President Barack Obama greets supporters after speaking at a campaign rally at Windham High School in Windham, New Hampshire, on August 18, 2012. (Credit: NICHOLAS KAMM/AFP/GettyImages)

Campaign 2012

US President Barack Obama speaks at a campaign rally in Rochester, New Hampshire, on August 18, 2012. (Credit: NICHOLAS KAMM/AFP/GettyImages)

Campaign 2012

A volunteer hands out campaign signs before US President Barack Obama speaks at a campaign rally in Rochester, New Hampshire, on August 18, 2012. (Credit: NICHOLAS KAMM/AFP/GettyImages)

Romney And Ryan Attend Town Hall Meeting In New Hampshire

August 20, 2012 in Manchester, New Hampshire. (Credit: John Moore/Getty Images)